One of the world’s hottest videogames, “League of Legends,” is disclosing a big jump in the number of customers playing its game each day.

Riot Games, of Santa Monica, Calif., said it now counts more than 27 million gamers playing “League of Legends” each day, more than double the 12 million it counted in October 2012. The company also said it has counted peaks of over 7.5 million customers playing the game at the same time each day, up 50% from the 5 million the company counted in March of last year.

Partially contributing to that success is the game’s business model. Like many online games these days, Riot doesn’t charge customers initially to play.

Customers can choose to play the game for free, or they can choose to pay for cosmetic items such as a different look for their character. The company also offers a rotation of various characters with different abilities that customers can play for free; customers can pay to play as a specific character when it is not available for free.

Payments by players have helped “League of Legends” become the second-largest game of its kind in 2013, raking in $624 million in revenue for the year, according to SuperData Research. “CrossFire,” a shooting game made by the South Korean developer SmileGate, is the only company considered larger, with sales of $957 million, SuperData said.

“League of Legends” and its success is a shining light for the videogame industry, particularly as sales of new videogames at retail stores in the U.S. continues to fall. That fall comes despite the launch of new videogame consoles from Microsoft and Sony, both of which have sold briskly since going on sale in November. In December, new game sales for videogame consoles and PCs dropped 11% to $1.31 billion, down from $1.58 billion the same time a year prior.

Other titles, such as Activision Blizzard’s “World of Warcraft,” charge customers a regular subscription, typically as much as $14.99 per month. The title is one of the most successful ever, reaching as many as 12 million paying subscribers in Oct. 2010. In November, Activision said it counted about 7.6 million subscribers.

Gamers and industry watchers say Riot’s success stems in part from its many tournaments, which pit top players from around the world against one another.

The last championship occurred in October in front of a sold-out crowd at the Staples Center in Los Angeles. The event was also watched online by more than 32 million people. The company held another competition on Saturday in front of a sold-out crowd in a 7,000 seat stadium in Korea.